Enterprises have become increasingly dependent on computer network infrastructures to provide services and accomplish mission-critical tasks. Indeed, the performance and efficiency of these network infrastructures have become critical as enterprises increase their reliance on distributed computing environments and wide area computer networks. The widely-used TCP/IP protocol suite, which is implemented widely throughout the world-wide data communications network environment called the Internet and many local area networks, omits any explicit supervisory function over the rate of data transport over the various devices that comprise the network. While there are certain perceived advantages, this characteristic has the consequence of juxtaposing very high-speed packets and very low-speed packets in potential conflict and produces certain inefficiencies. Certain loading conditions degrade performance of networked applications and can even cause instabilities which could lead to overloads that could stop data transfer temporarily. The above-identified U.S. Patents and patent applications provide explanations of certain technical aspects of a packet based telecommunications network environment, such as Internet/Intranet technology based largely on the TCP/IP protocol suite, and describe the deployment of bandwidth management solutions to monitor and manage network environments using such protocols and technologies.
Enterprises network topologies can span a vast array of designs and connection schemes depending on the enterprise's resource requirements, desired service levels, costs and the like. Enterprise network design topologies often include an array of access links interconnecting LAN and WAN segments in the enterprise's intranet, and multiple paths to extranets and the Internet. Enterprises that cannot afford the expense of private leased-lines to develop their own WANs, often employ frame relay, or other packet switched networks, together with Virtual Private Networking (VPN) technologies to connect private enterprise sites via a service providers public network or the Internet. Some enterprises also use VPN technology to create extranets with customers, suppliers, and vendors. Naturally, the cost of the access links and network infrastructures that interconnect enterprise networks and systems is an ever-growing concern.
Indeed, due to concerns over the cost of network bandwidth, the capacity of the access links that interconnect a given enterprise's WAN segments, as well as the access links connecting the enterprise WAN, often exceed a given enterprise's usage of that access link. For example, the costs often charged to a given enterprise for a given access link are based on usage. For example, many larger access links (e.g., Internet T1s, T3s) are billed according to a tiered rate structure based on a computed bandwidth consumption average. For example, while a given access link may support a transmission rate of 45 Megabits-per-second (Mbps), average bandwidth consumption over a month may be far less than this maximum rate. For example, an enterprise that consumes on average 6 Mbps over a given month is charged according to an applicable rate, while higher rates apply to larger average consumption values. According to one typical billing model, an Internet Service Provider may compute bandwidth charges for a given access link by taking the average bandwidth in bits-per-second (bps) in one-minute samples (or at some other sampling interval) over a given month (in both the inbound and outbound directions), discarding the top N percent (e.g., 5 percent) of the samples, and billing based on the highest remaining sampled value. These and similar billing models pose certain problems for enterprises since it is difficult to budget for such variable costs. For example, a single large file transfer during a given billing cycle could result in charges according to a higher rate tier. Accordingly, in these and similar billing models, enterprises sometimes deploy network traffic rate control devices, such as bandwidth or application traffic management systems, to limit bandwidth consumption on a given access link to a maximum bandwidth (e.g., 6 Mbps). In these deployments, as opposed to allowing traffic to burst and consuming the full capacity of the access link, the network traffic management devices prevent bandwidth charges from exceeding a given rate tier. From a performance standpoint, however, this solution is sub-optimal, since it does not allow the enterprise to take advantage of the excess capacity (e.g., bursting capability) of the access link when needed (such as when network application performance suffers due to increased load). In addition, this solution prevents an enterprise from capitalizing on the essentially free bursting capability allowed by the typical billing models, discussed above, which discard a percentage of the highest sample values.
In light of the foregoing, a need in the art exists for methods, apparatuses and systems directed to bandwidth management systems that adapt to network conditions, while managing tradeoffs between bandwidth costs and application performance. Embodiments of the present invention substantially fulfill this need.